"We're here to prevent work from happening to the extent we can do so.

"People in Victoria have a right to decide whether this project proceeds or not at the next election."

Last month several worksites were trashed when protests turned violent.

A bolstered police presence protecting the Alexandra Parade site is set to cost more than $336,000 in taxpayer funds.

The Linking Melbourne Authority, which is carrying out the drilling at the request of the three short-listed bidders to build the project, has said it will bore 16 new holes at sites in Fitzroy and Collingwood.

Transport Minister Terry Mulder said the final round of drilling on the $6 billion to $8 billion tunnel linking the Eastern Freeway to CityLink would be finished by January.

He said the extra drilling had the potential to save taxpayers tens of millions in construction costs.

"As part of preparing their proposals, bidders for the project have requested additional geotechnical testing so that they have a greater understanding of the underground conditions in the project corridor," Mr Mulder said yesterday.

"It is vitally important that the construction contractors have a detailed appreciation of the ground conditions, to help determine the best way for the project to be built."

Local council member Stephen Jolly said the cost of the project could be better spent improving Victoria's public transport system.

"If we build this tunnel there will be no money left over for other communities in Victoria for the transport and train projects they need," Mr Jolly said.

"Our fight isn't exclusive to the inner city. We're going to try and build resistance right throughout regional Victoria and metropolitan Melbourne."

Anti-East West protesters clashed violently with police last month and chaining themselves to equipment.

Mr Mulder said that while people had the right to protest, he hoped there would be no repeat of last month's ugly scenes.

"It is bad enough that these highly-skilled workers have to work behind fencing under police protection, but when so-called peaceful protesters charge police and attack a work site with heavy operating machinery, the community reacted with disgust," he said.

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